In a mission status report, NASA's Jet Propulsion Laboratory said the Mars Reconnaissance Orbiter resumed science operations on Tuesday. The orbiter unexpectedly rebooted its computer on June 3, and engineers brought it out of standby mode on June 6, NASA said. The time since then has been devoted to getting the orbiter's cameras and other instruments back on the job.

Engineers think the problem was caused by a cosmic ray or solar particle that hit the spacecraft's electronics.

Mars Reconnaissance Orbiter was launched in 2005 and entered Martian orbit in 2006. The probe has sent back thousands of high-resolution pictures of the Red Planet's surface, including snapshots of Mars landers and rovers as seen from space. Some of the imagery has
strengthened claims
that ancient Mars was shaped in part by flowing water.

The spacecraft's initial two-year, $720 million mission has been extended through at least 2010.

NASA said this month's reboot was reminiscent of a similar safe-mode event that occurred on Feb. 23. Engineers suspect that the earlier failure was also caused by a cosmic-ray hit. Such a hit could result in erroneous voltage readings that trigger a reboot, NASA said.

This report includes information from The Associated Press and msnbc.com.